The present invention relates to method and instruments for resection of the patella. Applicant has obtained two prior patents disclosing a patellar clamp, U.S. Pat. Nos. 4,706,660 and 4,633,862. These patents are related in that the former-mentioned patent arose out of an application which was a divisional application from the application from which the latter-mentioned United States Patent arose. These patents are incorporated herein by reference along with all prior art cited and discussed during the prosecution thereof.
The patellar clamp disclosed in the two above-mentioned prior United States Patents is designed to be used to install a patellar button prosthesis on a patella which has been predrilled for this purpose. The inventive clamp includes jaws designed to engage anterior and posterior surfaces of the patella to force projections of the patellar button prosthesis into openings preformed in the articular surface thereof. While the mechanism for moving the jaws toward and away from one another is similar in structure to corresponding structure of the present invention, as will be described in greater detail hereinafter, the purposes of the present invention are completely different from those disclosed in the prior patents and the structure for obtaining desired results also differs drastically therefrom.
Of the prior art made of record during the prosecution of the two above-mentioned prior United States Patents, except for those references discussed below, the references are believed to be of only general interest concerning the teachings of the present invention.
U.S. Pat. No. 395,262 to Butterworth discloses a bull ringer including a jaw B having a ring-like termination c designed to engage a portion of the nose of a bull whereupon a jaw C having a cutting punch a extends through the ring c to make an opening through the nose of the bull. The present invention differs from the teachings of Butterworth for reasons including provision of a slideably removable reamer guide device as well as a stop mechanism to limit the depth of reaming of the associated reamer device.
U.S. Pat. No. 4,444,180 to Schneider et al. discloses a clamp-like device wherein one of the jaws thereof comprises a drill guide having a plurality of holes of varying sizes therethrough as shown in FIG. 2 or, alternatively, as including a single large opening as illustrated in FIG. 5. The teachings of Schneider et al. differ from the teachings of the present invention for reasons including, again, removeability of the guide structure as well as a limit stop mechanism to prevent reaming of too much patellar structure.
Again, the references made of record during the prosecution of the above-mentioned prior patents are hereby made of record herein, but are believed to be of only general interest concerning the teachings of the present invention.